Blake Morrison, author of acclaimed memoirs And When Did You Last See Your Father? and Things My Mother Never Told Me, has written a fat summer read of a novel, panoramic and commercial. South of the River opens on 2 May 1997, the bright, slightly hungover morning after the New Labour landslide, when, to many people, all kinds of things suddenly seemed possible. Straddling the country (Suffolk) and city (south London) and spanning the subsequent five years, setting and sweep seem to promise us a state-of-the-nation novel. And there's certainly no shortage of contemporary name-checks, from Oxleas Wood to dotcoms, Equitable Life to Stephen Lawrence. But Blake Morrison's real preoccupations are much more domestic.

The novel is narrated by five characters: Libby, a successful advertising executive and mother; her husband, Nat, a failing playwright; Nat's uncle Jack, head of a family business and a master of foxhounds; and two former pupils of Nat's creative writing class, a black journalist called Harry and Anthea, an insecure and shiftless tree-hugger with nose rings.

The lives of these people are padded round with comfort - they're all implacably middle-class - but there is a dragging sense of unease in the atmosphere, a growing cynicism, disillusionment and fear. Foxes prowl through suburban gardens and lurk by the Thames. The animals are rumoured to be biting, even abducting, small children; something of their skulking cunning seems to have infected the humans.

Morrison absents himself from this, not letting us in on his conclusions about the point of it all. I wasn't sure what the different perspectives were meant to add up to. Possibly that hopes of regeneration have been lost in inertia, weak will and compromise? Yet this is not an angry novel. The characters endure the usual distresses - marriage break-up, bereavement - but they trudge on, just feeling more middle-aged.

The novel is good on the drabness of adultery and Nat, in particular, is drawn with real passion - deliciously self-deceiving and egotistical, even while his plays about suburban anomie are consistently rejected. His oversized sense of entitlement is a delight: he is faintly surprised to find himself missed off a list of leading cultural figures who have been invited to meet the Prime Minister.

Occasionally, the writing can be heavy-handed. The text of a politician's speech about foxhunting concludes: 'Thank you. [Finish. Applause. Quickly leave the platform, but then, as standing ovation continues, return several times to take bow?].' This is too crass for a politician and too much of a hostage to fortune: one thing to think it, another to put it on paper. And although the novel is billed as 'sexy' by the blurb, it's sexy in a very particular way. Anthea, mulling over her affair with Nat, thinks: 'And though he'd satisfied her afterwards, in more ways than one, she'd had few chances to see him since.' That 'in more ways than one' is a bit mimsy.

But these are quibbles. Blake Morrison has clearly set out to write an accessible romp, ripe for the summer market, as much about middle-class adultery as about anything else, though with a clever, sour tone. In this, he has succeeded just fine.